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Comparison of the fixed versus the removable functional braces in the treatment of children with sticking out top front teeth

Condition category

Oral Health

Date applied

01/06/2016

Date assigned

03/06/2016

Last edited

08/06/2016

Prospective/Retrospective

Prospectively registered

Overall trial status

Ongoing

Recruitment status

Recruiting

Plain English Summary

Background and study aimsSticking out top front teeth is a very common problem amongst children in the UK, and is caused by incorrect alignment of the top and bottom jaws (malocclusion). This can result in more injuries to these teeth as a result of accidents. It has also been shown that a child’s confidence and the smile can be really affected by this appearance. The alignment of the jaws and the self-esteem of affected children can be improved using a functional appliance, which is a special type of brace that works by holding the bottom jaw in a forward position, to encourage more natural growth of the jaws. Functional braces may be either fixed by glue onto the teeth, or removable. The most popular type of removable functional appliance is called the Twin-Block, and the most popular fixed type is the Herbst. The aim of this study is to compare the effectiveness of fixed and removable functional braces for the treatment of children with sticking out top front teeth.

Who can participate? Children aged 10-14 with sticking out top front teeth (class II malocclusion)

What does the study involve? At the first visit, as in routine practice, the following procedures are undertaken: mouldings of the child’s teeth and bite using a putty material, an X-ray of the child’s jaws and teeth to check teeth development and jaw alignment, and photographs to assess the child’s teeth and face. Taking part in the study also involves the following two additional tasks: children are asked to fill in a questionnaire booklet to help better understand how the bite/appearance has affected their confidence and quality of life, and they undergo a three-dimensional facial scan, similar to a photograph, to assess the jaw line. At the second visit, the child has further moulds taken to make the functional brace. At the third visit, participants are randomly allocated to be treated with one of two braces: the fixed Herbst brace or the Twin Block brace. The Herbst brace is glued to the teeth and is not possible to take out, whereas the Twin Block is removable, and the child is advised to wear it 24 hours a day (except during swimming and contact sport). The children are then seen every 4-6 weeks (as in normal brace treatment) to check the brace, measure the amount of correction in the top teeth sticking out, and to record their experiences and compliance with the treatment. The treatment with the functional brace ends when the bite is fully corrected and the top teeth no longer stick out. This may take 6-12 months. At this point, and directly after removing the functional brace, we ask the child to complete the questionnaires and undergo a facial scan again. In addition, in line with routine functional brace care, an x-ray is taken. As with all children receiving functional braces, the child is then assessed to see if they would benefit from having train-track fixed braces. This treatment can last a further 12-18 months depending on the bite and how crooked the teeth are. If the child does not require train track braces, their treatment ends after the functional brace. If the child has the train track brace, he/she completes the questionnaires, facial scan and x-ray again when this treatment is completed.

What are the possible benefits and risks of participating? The child’s sticking out front teeth and bite problem will be treated by experienced orthodontists. The information we get from this study will help improve the future treatment of children with similar problems. There are no expected risks to the child for taking part in this study. We routinely provide children these braces and follow-up care detailed above. There is a possibility that this treatment, like all brace treatment, may cause some discomfort and side effects, e.g. breakage, loss of the brace, and mouth sores or ulcers due to brace rubbing. The child will be given all the care instructions to help avoid any of these problems when the brace is fitted.

Where is the study run from? 1. Barts and the London Health Trust (UK)2. East Kent Hospitals University NHS Foundation Trust (UK)

When is the study starting and how long is it expected to run for? October 2016 to April 2019

Who is funding the study? 1. Queen Mary University of London (UK)2. Barts Health NHS Trust (UK)

Who is the main contact? Dr Moaiyad Moussa Pacham.mossapacha@qmul.ac.uk

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

Study information

Scientific title

A comparison of the effectiveness of fixed versus removable functional appliances in the treatment of Class II malocclusion in children: a randomised clinical trial

Acronym

Study hypothesis

Sticking out top front teeth is a very common problem amongst children in the UK, which is associated with deviation of normal occlusion between the top and bottom jaws. This type of malocclusion can result in more injuries to these teeth as a result of accidents. It has also been shown that a child’s confidence and the smile can be really affected by this appearance. Treatment is aimed at improving the occlusal outcome and self-esteem of affected children using what is called functional appliance. A functional appliance is a special type of brace to correct the bite and sticking out top front teeth. It works by holding the bottom jaw in a forward position in growing children, to encourage more natural growth of the jaws. Functional braces may be either a fixed, by glue onto the teeth, or a removable. The most popular type of removable functional appliance is called the Twin-Block, and the most popular fixed type is the Herbst.

The null hypotheses are there will be no significant differences between these appliances with regard to: treatment duration, patient-reported perception and impact of the appliance (quality of life; self-esteem; aesthetics & function), skeletal and dental effects (cephalometric and PAR score) and cost-effectiveness.

Ethics approval

London City & East NHS Research Ethics Committee - submission pending

Study design

Randomised parallel-group study design with a positive control group

Primary study design

Interventional

Secondary study design

Randomised parallel trial

Trial setting

Hospitals

Trial type

Treatment

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

Class II division 1 malocclusion

Intervention

This trial will compare the effectiveness of an Hanks-Herbst fixed and Twin-Block removable functional appliance in the correction of Class II division 1 malocclusion. Treatment will be provided by four clinicians in a two-centre study in the UK: Bart’s NHS Health Trust and East Kent Hospitals University NHS Foundation Trust. Moreover, an independent data monitoring committee (DMC) will be assigned, and the trial will conform to the recommendations of the UK’s Medical Research Council for good clinical practice and in line with CONSORT guidelines (Schulz et al., 2010).

Patients who fulfil the selection criteria and are willing to participate will be asked to complete an assent form and their parents a consent form, after reading a participant information leaflet. Treatment allocation will be performed centrally at Queen Mary University. The duration of participants in the trial will be 12-36 months. This includes the length of functional treatment phase (6-12 months) followed by the second phase of FA treatment (12-18 months) if the clinician decides that it is necessary to achieve an optimal occlusal relationship.

Participants will randomly (like tossing a coin) be allocated to one of the two different functional brace options: Fixed Herbst brace OR Twin Block brace. To improve the quality of the study neither the child or the researcher will decide or know which brace the child will receive.

At the first visit, and in the line of routine orthodontic practice, the following procedures will be undertaken in order to best help decide on child treatment:1. Mouldings of child’s teeth and bite, using a putty material (5 minutes to complete)2. An X-ray for child’s jaws and teeth, to check teeth development and jaws alignment (10 minutes to complete)3. Photographs to assess child’s teeth and face (5 minutes to complete)Taking part in the study will involve the following two additional tasks:4. Questionnaires. Children will be asked to fill and answer a questionnaire booklet independently in the hospital, to help better understand how the bite/appearance have affected child’s confidence and their quality of life (15 minutes to complete)5. Three-dimensional facial scan, similar to undergoing a photographs, to assess the jaw line (1 minute to complete)

At the second visit, the child will have further moulds done to fabricate the functional brace.

At the third visit, the child will receive either the Herbst or Twin Block brace. The Herbst brace will be glued to the teeth, and will not be possible to take it out, whereas the Twin Block is removable, and the child will be advised to wear it 24 hours a day (except during swimming and contact sport).

Follow-up visits, the child will then be seen every 4-6 weeks (as in normal brace treatment), to check the brace, measure the amount of correction in the top teeth sticking out, and to record his/her experiences and compliance with the treatment. The treatment with functional brace will end when the bite is fully corrected and the top teeth no longer stick out. This may take 6-12 months to be completed. At this point, and directly after removing the functional brace, we will request the child to complete the questionnaires and a facial scan again. In addition, in line with routine functional brace care, an x-ray will be taken.

Train track brace: as with all children receiving functional braces, the child will then be assessed if would benefit from having train-track fixed braces. This treatment can last a further 12-18 months depending on the bite and how crooked the teeth are. If the child does not require train track braces, their treatment will be ended after the functional brace. If the child has the train track brace, he will complete the questionnaires, facial scan and x-ray again when this treatment is completed.

Intervention type

Device

Phase

Drug names

Primary outcome measures

1. The effectiveness in terms of morphological changes (skeletal, soft tissue and dento-alveolar)2. The duration of functional treatment until the full reduction of the overjet (0-2mm)

The measurements will be undertaken at the following points:1. T0, at the baseline and before commence treatment2. T1, at the end of functional phase of treatment and directly after removal the functional brace (6-12 months), when the sticking out teeth (the overjet) is a full reduced to within normal value (0-2 mm)3. T2, if the children is assessed to have a second phase of treatment using train-track brace, then a third measurements will be undertaken after achieving an ideal occlusion relationship (18-30 months)

Secondary outcome measures

The measurements will be undertaken at the following points:1. T0, at the baseline and before commence treatment2. T1, at the end of functional phase of treatment and directly after removal the functional brace (6-12 months), when the sticking out teeth (the overjet) is a full reduced to within normal value (0-2 mm)3. T2, if the children is assessed to have a second phase of treatment using train-track brace, then a third measurements will be undertaken after achieving an ideal occlusion relationship (18-30 months)

Participant type

Patient

Age group

Child

Gender

Both

Target number of participants

80: A sample size calculation was performed. On the basis of which a 4-month (SD 4.61) difference in treatment duration is regarded as a clinically relevant difference in treatment duration between these two modalities. This provides a sample size of 40 patients in each group, allowing for a non-compliance rate of 30% with a power of 85% and an alpha of 0.05.